Dual cylinder brake



Dec. 20, 1966 E. K. DOMBECK 3,292,745

DUAL CYLINDER BRAKE Original Filed Oct. 2'7, 1964 5 Sheets-Sheet 1 EIE J.

INVENTOR.

EDWARD K. DOMBECK.

BYM

A TTOR/VE r.

Dec. 20, 1966 E. K. DOMBECK 3,

DUAL CYLINDER BRAKE Original Filed Oct. 27, 1964 s Sheets-Sheet z y I IE E I NVENTOR.

EDWARD K. DOMBECK.

,4 TTOR E Y Dec. 20, 1966' E. K. DOMBECK 3,292,745

DUAL CYLINDER BRAKE Original Filed Oct. 27, 1964 5 Sheets-Sheet 5 :51 E E A I N VEN TOR.

Dec. 20, 1966 E. K. DOMBECK 3,292,745

DUAL CYLINDER BRAKE Original Filed 001:. 27, 19 64 5 Sheets-Sheet 4 WWW mm! I INVENTOR.

A TTORNE Y EDWARD K. DOMBECK.

Dec. 20, 1966- E. K. DOMBECK 3,292,745

DUAL CYLINDER BRAKE Original Filed Oct. 27, 1964 v 5 Sheets-Sheet 5 INVENTOR.

EDWARD K. DOMBECK 2 4M, A a; M

A TTORNEY.

United States Patent 3,292,745 DUAL CYLINDER BRAKE Edward K. Dombeck, South Bend, Ind., assiguor to The Bendix Corporation, a corporation of Delaware Continuation of application Ser. No. 406,929, Oct. 27, 1964. This application Feb. 25,1966, Ser. No. 536,521 Claims, (Cl. 188152) This application is a continuation-in-whole of copending application Serial No. 406,929, filed October 27, 1964, which, in turn, is a continuation-in-part application of parent application Serial No. 210,768, filed July 18, 1962, both now abandoned.

This invention relates to a drum brake and more particularly to a drum brake for use on a vehicle having a small wheel base diameter and requiring a large braking force for stopping the vehicle.

One of the objects of this invention is to provide a brake having a set of brake shoes slidably mounted on each side of a backing plate.

Another object of this invention is to provide a brake with a wheel cylinder mounted on each face of a backing plate wherein the fluid chambers of each wheel cylinder are interconnected with each other.

A further object of the invention is to provide a brake having a set of brake shoes slidably mounted on each side of a backing plate with a manual control for parking brake operation.

Still another object of the invention is to provide a brake having a set of brake shoes slidably mounted on each side of a backing plate with a shoe hold-down device.

A still further object of the invention is to accomplish the above objects with the utilization of as many standard parts as possible.

Other objects and features of the invention will become apparent from a consideration of the following description wherein a selected example embodiment has been chosen to illustrate the invention. The description proceeds with a reference to the accompanying drawing wherein:

FIGURE 1 illustrates a front elevational view of a brake assembly of the invention;

FIGURE 2 is a view taken along section line 2-2 of FIGURE 1;

FIGURE 2A is a view similar to FIGURE 2 only a modification thereof;

FIGURE 2B is a View similar to FIGURE 2A only a modification thereof;

FIGURE 3 is a view taken along section line 3--3 of FIGURE 1;

FIGURE 4 is a side elevational view of an actuating lever utilized for parking brake operation;

FIGURE 5 is a partial front elevation view of a modified embodiment for parking brake operation;

FIGURE 6 is a view taken along section line 6-6 of FIGURE 5;

FIGURE 7 is a view taken along section line 77 of FIGURE 5; and

FIGURE 8 is a view taken along section line 88 of FIGURE 1 illustrating a shoe hold-down device.

Referring to FIGURES 1 and 2, a backing plate 10 is provided which may be attached to a stationary part of a vehicle, as for instance, a spindle (not shown). A pair of T-shaped brake shoes 12, 12a are slidably mounted on one face of the backing plate 10 and a pair of brake shoes 14, 14a (FIGURE 8) are slidably mounted on able strut 20 is located between and interconnects one set of adjacent ends of the brake shoes of each set and a spring 22 holds the ends of the brake shoes in engage ment with the adjustable strut 20. An anchor pin 24 is secured to the backing plate 10 and located between the other adjacent ends of each pair of brake shoes of each set for anchoring abutment thereof. A retainer plate 11 is provided to laterally locate the ends of each pair of brake shoes with respect to the anchor pin 24.

A wheel cylinder 26 is provided on one side of the backing plate for actuating the set of brake shoes 12, 12a and a wheel cylinder 28 is provided on the other face of the backing plate for actuating the other Set of brake shoes 14, 14a. Each wheel cylinder has an ear 30 and flange 32 each having an opening therein. The anchor pin 24 extends through the opening of the ears 30 with the nuts 34 pressing the ears into engagement with a backing plate. A bolt and nut assembly 36 extends through the openings in the flanges 32 for pressing the flanges into engagement with the backing plate thereby resulting in fixing the Wheel cylinders to the backing plate. The wheel cylinder 26 has a boss 37 extending therefrom which has an inlet port 38 and an outlet port 40 communicating with the wheel cylinder fluid chamber 42. The wheel cylinder 28 has a boss 44 extending therefrom having an inlet port 46 and an outlet port 48 communicating with the fluid chamber 50. Each boss has a flange 52 for engaging the backing plate surfaces or faces. The wheel cylinder 28 further has an inlet port 54, communicating with a master cy-. linder, and a bleeder port 56. The backing plate has an opening 58 into which each boss 36 and 44 extend. The extent to which the bosses may be placed intothe opening 58 is limited by engagement of the ear 30 and the flanges 52 on the backing plate faces. The inlet port 38 and outlet port 48 are aligned and the inlet port 46 and the outlet port 40 are aligned. Each boss has aligned annular notches which receive an O- ring 60 for separating the aligned ports 46 and 40 from the other aligned ports 38 and 48 and each boss has a shoulder therein which forms an annular notch when the bosses abut each other for receiving another O-rin'g 53 which separates the aligned ports from the exterior of the wheel cylinders. Thus, it can -be seen that fluid communicated to the inlet nozzle 54 will travel to each fluid chamber 42 and 50 and when it is desired to bleed the wheel cylinder fluid chambers, the fluid will pass through ports 40 and 46 and bleed port 56. A thrust element 62 of each respective wheel cylinder interconnects a piston 64 with the brake shoe 12 of one set of brake shoes and the brake shoe 14 of the other set of brake shoes. Assuming rotation of the brake drum in the direction of the arrow A, the brake shoes 12 and 14 will be the leading brake shoes and the brake shoes 12a and 14a will be the trailing brake shoes. Upon actuation of the wheel cylinders the thrust element 62 will thrust the brake lining 13 of the brake shoes 12 and 14 against the brake drum surface and upon engagement of the friction linings with the brake drum the shoes 12 and 14 will tend to rotate the brake drum thereby transferring their movement to the brake shoes 12a and 14a through the struts 20 effecting engagement of the linings of brake shoes 12a and 14a with the drum 14. Upon release of the pressure in the wheel cylinders, springs 66 will urge the brake shoes to retracted position. While a wheel cylinder having one piston for spreading only one shoe has been illustrated, obviously an opposed piston wheel cylinder for spreading both shoes of a set may be utilized.

Referring to FIGURE 2A, there is illustrated a modified version of an interconnection between two wheel cylinders. All elements which are similar to those of FIGURE 2 are designated with the same reference numeral with an a aflixed thereto. In this instance the support a comprises two superimposed plates 200 and 202 secured together. Each of the bosses 37a and 44a of the wheel cylinders 26a and 28a, respectively, has a flat face 204 and 206, respectively, which engages an exposed surface of a respective one of the plates 200 aand 202. Each of the ports 38a, 40a, 46a, and 48a has a sealing ring receiving counterbored portion 208 opening into a respcctive one of the end faces 204 and 206. .Each of the counterbored portions 208 comprises a shoulder 210 extending transversely to the annular wall thereof. The plate 200 has a pair of openings 212,214 and the plate 202 has a pair of openings 216, 218 which are aligned with openings 212 and 214, respectively. The set of openings 212 and 216 are aligned with the wheel cylinder ports 3821 'and' 48a fand the set' of openings 214 and 218 are aligned with the wheel cylinder ports 40a and 46a. An annular spacer member 220 is located within the openings 212 and 216 and an annular spacer member 222 is located within the openings 214 and 218. A resilient sealing ring 224 is located in each of the counterbored portions of the ports and are compressed between a respective end of the spacer members and a respective shoulder 210 to provide fluid tight communication between the ports 38a and 48a and the ports 40a and 46a- Referring to the embodiment in FIGURE 2B, the elements which are similar to those in the embodiment of FIGURE 2A are designated with the same reference numerals with a b aflixed thereto. This embodiment differs from the embodiment in FIGURE 2A in that the support 10b is a single plate and the ports 38b and 48b are communicated directly through anppening 300 in the support plate 10b and the ports 40b and 46b are communicated directly through the opening 302 in the support plate 10b rather than communicated through spacer members. The sealing rings 224 are compressed between their respective faces on the support plate 10b and their respective shoulders 21012 of the counterbored portion 208b of the ports to provide a fluid tight connection between the ports 38b and 48b and the ports 40b and 46b.

Parking brake For parking brake operation, a lever 70 is pivotally mounted at one end to the web of the brake shoe 12 and a lever 72 is pivotally mounted at one end to the brake shoe 14a. A strut 74 interconnects the lever 70 with the brake shoe 12a and a strut 76 interconnects the lever 72 with the brake shoe 14. Springs 78 are carried by a portion of each strut for preventing rattling of the strut which is retained within a notch of their respective brake shoes. A slot 79 is provided in the backing plate for receiving a parking brake actuating lever 80 which extends on both sides of the backing plate and is constructed of two stampings 82 and 84 welded together at their ends and spread apart intermediate the ends. Two pins 86 extend between the spread apart portions of the stampings 82 and 84 and are engaged by springs 88 slidably compressed between the backing plate and the pins 86 for holding the lever 80 in position. A cable 90 is attached to the lever 70 and has an abutment 92 which is inserted through the wider opening 94 of the lever 80 and then held in place by the narrower opening and notch 96. A cable 98 is attachcd'to the lever 72 and has an abutment 100 at the end thereof which is inserted through the wider opening 94 of the lever 80 and held in position by the narrower opening and notch 102. Springs 104 are compressed between the lever 70 and lever 80 and between lever 72 and lever 80 for urging the levers 70 and 72 to their retracted position. Upon applying a force P to the end 106 of the lever 80, the lever 80 will fulcrum about the abutment 92 and 100 until the levers 70 and 72 are drawn toward each other to bring the linings of their respective brake shoes into engagement with the drum. Upon release of the lever 80 the springs 66 will urge the brake shoes to they are in no way restrictive of the invention.

their retracted position and the springs 104 will urge the. levers 70 and 72 to their respective retracted positions.

Referring to FIGURES 5-7 for the modified embodi- ,2

ment of the lever connection for parking brake operation,

similar structure to the previous embodiment is illustrated by like reference numerals with primes attached thereto. The backing plate 10 has a downwardly turned flange 122 and a parking brake lever is pivotally attached to the flange 122 by a bolt 124. bracket 126 is rigidly attached to the end 128 of the lever A generally U-shaped 80 by a rivet 130. The levers 70' and 72' are .now: axially aligned, one behind the other, and are therefore: each on the same side of the lever 80' and both must be pulled in the same direction for spreading the brake;

shoes.

A cable 132 has one end thereof attached-to the lever 70 and the other end attached to the lever 72 and has a portion intermediate its ends extending through the U-shaped bracket. The U-shaped bracket has flanges 13.4 Y which serve as abutting surfaces for the springs 104' which urge the lever 70 and 72' to their retracted positions.

Upon movement of the parking brake lever 80' by they force P the parking brake lever will move the bracket brake shoes.

thereby moving the levers 70' and 72' for spreading the 1 Obviously separate cables could be used.

to connect levers 70' and .72 to the bracket 126 rather than a single cable 132.

- Referring to FIGURE 8, there is illustrated a brake hold-down device consisting of a pin 108 extending through aligned openings 110 in the webs of brake shoes 12a and 14a and an aligned opening 112 of the backing plate.

A spring 114 is compressed between a plate 116 i which engages its respective web of a brake shoe and a '1 cup 118 which is held from outward movement by each i end 120 of the pin 108. The brake shoes are therefore biased toward each other and into engagement with the backing plate by the brake shoe hold-down device.

of the invention and therefore it is intended that such revisions and variations as incorporate the herein disclosed principles, will be included within the following claims as equivalents thereof.

I claim:

1. In a drum brake comprising: a support member having a pair of opposed surfaces thereon, a pair ofwheel cylinders each having a boss thereon, each of said bosses having a generally flat end face, means securing said wheel cylinders to said support member in such a manner that the flat end face of the boss of one of said wheel cylinders engages one of said opposed surfaces and the fiat end face of the boss of the other of said 3 wheel cylinders engages the other of said opposed surfaces, one of said wheel cylinders having a hose inlet opening and a bleeder opening communicating with'its respective wheel cylinder fluid chamber, each boss having an inlet port and an outlet port communicating with its respective wheel cylinder fluid chamber, a pair of spaced 1 openings in said supportmember, said wheel cylinders being arranged on said support member so that one of said openings of said support member is aligned with i the inlet port of one of said bosses and the outlet port of the other of said bosses and the other of said openings.

of said support member is aligned with the outlet port of said one boss and the inlet port of said other boss, an annular spacer member in each of said openings of said L support member, a plurality of resilient members surrounding a respective one of said ports and being compressed between its respective end face and its respective end of said spacer member to provide a fluid tight connection between each set of opposing inlet and outlet ports.

2. In a drum brake comprising: a support member having a pair of opposed surfaces thereon, a pair of wheel cylinders each having a boss thereon, each of said bosses having a generally flat end face, means securing said wheel cylinders to said support member in such a manner that the flat end face of the boss of one of said wheel cylinders engages one of said opposed surfaces and the flat end face of the boss of the other of said wheel cylinders engages the other of said opposed surfaces, one of said wheel cylinders having a hose inlet opening and a bleeder opening communicating with its respective wheel cylinder fluid chamber, each boss having an inlet port and an outlet port communicating with its respective Wheel cylinder fluid chamber, a pair of spaced openings in said support member, said wheel cylinders being arranged on said support member that one of said openings of said support member is aligned with the inlet port of one of said bosses and the outlet port of the other of said bosses and the other of said openings of said support member is aligned with the outlet port of said one boss and the inlet port of said other boss, a plurality of resilient members, each of said resilient members surrounding a respective one of said ports and being compressed between its respective end face and its respective support member surface to provide a fluid tight connection between each set of opposing inlet and outlet ports.

3. In a drum brake comprising: a support member having a pair of opposed surfaces thereon, a pair of wheel cylinders each having a boss thereon, each of said bosses having a generally flat end face, means securing said wheel cylinders to said support member in such a manner that the flat end face of the boss of one of said wheel cylinders engages one of said opposed surfaces and the flat end face of the boss of the other of said wheel cylinders engages the other of said opposed surfaces, one of said wheel cylinders having a hose inlet opening and a bleeder opening communicating with its respective wheel cylinder fluid chamber, each boss having an inlet port and an outlet port communicating with its respective wheel cylinder fluid chamber, each of said ports having a counterbored portion opening into the face of its respective boss, each counterbored portion including an annular wall and an annular shoulder extending transversely to said Wall and spaced from said face, a pair of spaced openings in said support member, said wheel cylinders being arranged on said support member that one of said openings of said support member is aligned with the inlet port of one of said bosses and the outlet port of the other of said bosses and the other of said openings of said support member is aligned with the outlet port of said one boss and the inlet port of said other boss, a resilient member located in each counterbored portion of said ports and compressed between its respective said annular shoulder and its respective support member surface to provide a fluid tight connection between each set of opposing inlet and outlet ports.

4. In a drum brake comprising: a support member comprising two plates secured together with the inner faces thereof being superimposed upon each other and the outer faces thereof being exposed and facing opposite directions, a pair of wheel cylinders each having a boss thereon, each of said bosses having a generally flat end face, means securing said wheel cylinders to said support member in such a manner that the flat end face of the boss of one of said wheel cylinders engages the outer surface of one of said plates and the flat end face of the boss of the other of said wheel cylinders engages the outer surface of the other of said plates, one of said wheel cylinders having a hose inlet opening and a bleeder opening communicating with its respective wheel cylinder fluid chamber, each boss having an inlet port and an outlet port communicating with its respective wheel cylinder fluid chamber, a first set of aligned openings in said plates, a second set of aligned openings in said plates, said wheel cylinders being arranged on said plates that one set of openings is aligned with the inlet port of one of said bosses and the outlet port of the other of said bosses and the other set of openings are aligned with the outlet port of said one boss and the inlet port of said other boss, an annular spacer member in each set of openings, a plurality of resilient members, each of said resilient members surrounding a respective one of said ports and being compressed between its respective end face and its respective end of said spacer member to provide a fluid tight connection between each set of opposing inlet and outlet ports.

5. In a drum brake comprising: a support member comprising two plates secured together with the inner faces thereof being superimposed upon each other and the outer faces thereof being exposed and facing opposite directions, a pair of wheel cylinders each having a boss thereon, each of said bosses having a generally flat end face, means securing said wheel cylinders to said support member in such a manner that the flat end face of the boss of one of said wheel cylinders engages the outer surface of one of said plates and the flat end face of the boss of the other of said wheel cylinders engages the outer surface of the other of said plates, one of said wheel cylinders having a hose inlet opening and a bleeder opening communicating with its respective wheel cylinder fluid chamber, each boss having an inlet port and an outlet port communicating with its respective Wheel cylinder fluid chamber, each of said ports having a counterbored portion opening into the face of its respective boss, each counterbored portion including an annular wall and an annular shoulder extending transversely thereto and spaced from said face, a first set of aligned openings in said plates, a second set of aligned openings in said plates, said wheel cylinders being arranged on said plates that one set of openings is aligned with the inlet port of one of said bosses and the outlet port of the other of said bosses and the other set of openings is aligned with the outlet port of said one boss and the inlet port of said other boss, an annular spacer member in each set of openings, a resilient member located in each counterbored portion of said ports and compressed between its respective said annular shoulder and its respective end of said spacer member to provide a fluid tight connection between each set of opposing inlet and outlet ports.

References Cited by the Examiner UNITED STATES PATENTS 2,496,562 2/1950 Schnell 188-152 FOREIGN PATENTS 788,586 1/1958 Great Britain.

MILTON BUCHLER, Primary Examiner. G. E. A. HALVOSA, Assistant Examiner. 

1. IN A DRUM BRAKE COMPRISING: A SUPPORT MEMBER HAVING A PAIR OF OPPOSED SURFACES THEREON, A PAIR OF WHEEL CYLINDERS EACH HAVING A BOSS THEREON, EACH OF SAID BOSSES HAVING A GENERALLY FLAT END FACE, MEANS SECURING SAID WHEEL CYLINDERS TO SAID SUPPORT MEMBER IN SUCH A MANER THAT THE FLAT END FACE OF THE BOSS OF ONE OF SAID WHEEL CYLINDERS ENGAGES ONE OF SAID OPPOSED SURFACES AND THE FLAT END FACE OF THE BOSS OF THE OTHER OF SAID WHEEL CYLINDERS ENGAGES THE OTHER OF SAID OPPOSED SURFACES, ONE OF SAID WHEEL CYLINDERS HAVING A HOSE INLET OPENING AND A BLEEDER OPENING COMMUNICATING WITH ITS RESPECTIVE WHEEL CYLINDER FLUID CHAMBER, EACH BOSS HAVING AN INLET PORT AND AN OUTLET PORT COMMUNICATING WITH ITS RESPECTIVE WHEEL CYLINDER FLUID CHAMBER, A PAIR OF SPACED OPENINGS IN SAID SUPPORT MEMBER, SAID WHEEL CYLINDERS BEING ARRANGED ON SAID SUPPORT MEMBER SO THAT ONE OF SAID OPENINGS ON SAID SUPPORT MEMBER IS ALIGNED WITH THE INLET PORT OF ONE OF SAID BOSSES AND THE OUTLET PORT OF THE OTHER OF SAID BOSSES AND THE OTHER OF SAID OPENINGS OF SAID SUPPORT MEMBER IS ALIGNED WITH THE OUTLET PORT OF SAID ONE BOSS AND THE INLET PORT OF SAID OTHER BOSS, AN ANNULAR SPACER MEMBER IN EACH OF SAID OPENINGS OF SAID SUPPORT MEMBER, A PLURALITY OF RESILIENT MEMBERS SURROUNDING A RESPECTIVE ONE OF SAID PORTS AND BEING COMPRESSED BETWEEN ITS RESPECTIVE END FACE AND ITS RESPECTIVE END OF SAID SPACER MEMBER TO PROVIDE A FLUID TIGHT CONNECTION BETWEEN EACH SET OF OPPOSING INLET AND OUTLET PORTS. 